Sc3Ir4Si13+x and Sc4Ir7Ge6 – the perovskite-related crystal structures

Abstract

Abstract The crystal structure of Sc3Ir4Si13+x (x = 0.22) [space group Pm3‾n$Pm‾{3}n$, a = 8.4651(1) Å] is found to be a new disordered variant of the primitive cubic Yb3Rh4Sn13 Remeika prototype. The silicide is stable in the narrow temperature range of 1283–1397 °C and reveals metallic properties. The crystal structure of Sc4Ir7Ge6 [U4Re7Si6 type, space group Im3‾m$Im‾{3}m$, a = 8.1397(8) Å] is refined for the first time. The electronic band structure calculations reveal that the properties of this germanide can be explained based on the free electron gas model. Both compounds reveal close structural relationships to the simple perovskite structure.